Risky Driving

Drug-Impaired Driving

Overview

Prescription drugs, over-the-counter medications, and illegal drugs may cause impairment alone or in combination with each other and/or with alcohol. In every State and the District of Columbia, impaired driving is illegal. Whether by drugs — legal or illegal — alcohol, or a combination of both drugs and alcohol, impaired driving puts the driver, their passengers, and other road users at risk. In NHTSA’s National Roadside Survey conducted in 2013-2014, 20 percent of drivers surveyed tested positive for potentially impairing drugs. Let’s work together to share this life-saving message: Impaired driving is illegal and deadly.

Press Release

Put Safety First This St. Patrick’s Day: Plan a Safe Way Home, Before You Start to Drink

Drug-Impaired-Driving Trends

While we’ve long studied and understood the dangers involving drunk driving, we are still researching and learning about the effects of drugs on driving. Meanwhile, it has become an increasing public and governmental concern in the United States.

The 2013-2014 Roadside Survey of Alcohol and Drug Use by Drivers found an increase in the number of drivers testing positive for marijuana and other drugs that can impair driving skills compared to the 2007 survey findings. In the 2013-2014 survey, nearly one in four drivers tested positive for at least one drug that could potentially affect safe driving skills.

Drug-impaired driving is an important safety issue that NHTSA continues to research. The agency is working to develop new knowledge on how drugs affect driving, to grow new and enhance existing programs to reduce drug-impaired driving.

The Issue

How Marijuana Affects Driving

In recent years, State actions to legalize the use of marijuana for medical and recreational use have increased concern over potential risks of driving impaired by marijuana. Other than alcohol, it is the drug that is most frequently detected in drivers’ systems after a vehicle crash, as well as the general driving population (Compton & Berning, 2017; Kelley-Baker et al., 2017; Lacey et al., 2009; Walsh et al., 2005).

NHTSA’s Crash Risk Study, the largest of its kind ever conducted, assessed whether marijuana use by drivers is associated with greater risk of crashes. The survey found that marijuana users are more likely to be involved in crashes, but that the increased risk may be due in part because marijuana users are more likely to be in groups at higher risk of crashes. In particular, marijuana users are more likely to be young men – a group already at high risk. NHTSA is conducting another crash risk study, however; this time, only serious injury and fatal crashes will be investigated.

We know that marijuana can be dangerous when combined with driving. Studies show that marijuana impairs psychomotor skills, lane tracking, and cognitive functions (Robbe et al., 1993; Moskowitz, 1995; Hartman & Huestis, 2013), but it is still unclear the extent to which it contributes to the occurrence of vehicle crashes. Some studies have attempted to estimate the risk of driving after marijuana use (Li et al., 2012; Asbridge et al., 2012), but these remain inconclusive in terms of predicting real-world crash risk.

NHTSA In Action

NHTSA’s National Drug-Impaired Driving Initiative

On January 25, the U.S. Department of Transportation’s (DOT) National Highway Traffic Safety Administration (NHTSA) launched a new initiative to combat drug-impaired driving, a form of impaired driving that is illegal in all 50 States and the District of Columbia. With a national opioid epidemic and States legalizing marijuana to varying degrees, NHTSA is making drug-impaired driving a top priority. Goals include:

Starting a national dialogue and developing strong policies;

Launching a public awareness and education initiative to stigmatize drug-impaired driving; and

July 16: King kicks off regional stakeholder dialogues

NHTSA Deputy Administrator Heidi King was in Seattle on July 16 for the first of many regional meetings to advance the agency's initiative to lead a national dialogue on combating drug-impaired driving. Read her remarks.

Drug-Impaired Driving Summit (March 15): To kick off the new initiative, NHTSA hosted a summit to bring together key stakeholders — including safety partners, State and local elected officials, data and policy experts, law enforcement and criminal justice professionals, toxicologists, and drug recognition experts — to address drug-impaired driving.

Two expert panels described the nature of the problem and discussed ways to address it. Law enforcement leaders shared their experiences from the streets. Scientists reported the types of drugs detected in drivers and explained how various drugs impair driving functions. Policy experts reviewed programs and resources and discussed experience with State laws.

Safety officials and criminal justice professionals are relying on methods that have proven effective for addressing the alcohol-impaired driving problem but face uncertainty about how some of the approaches apply to drug use.

Expert panelists and participants agreed on the urgent need for a coordinated plan to address the problem. A number of best practices were presented, demonstrating the potential for making near-term progress while new tools are developed to identify and measure impairment by a new and rapidly changing array of drugs.

As a result of the summit, NHTSA has identified steps it will take over the next year to better understand and address drug-impaired driving. They include:

Research to Improve Our Understanding of Drug-Impaired Driving

DOT and NHTSA are teaming up with law enforcement and scienctists to improve the agency's understanding of drug-impaired driving.

Over the next 12 months, NHTSA will:

Examine the operation of new oral fluid screening devices that could be used by law enforcement to screen drivers for drugs in a matter of minutes and

Update its fatality data collection system to get more detailed data on drug-related fatal crashes for calendar year 2018.

NHTSA is working to improve the information in FARS on drug use by drivers. In 2018, small improvements, such as changes to the drug list and allowing more than three drugs to be listed, will be underway. More significant improvements will happen in 2019 and 2020 (e.g., distinguishing between screening tests and confirmatory tests, recording quantity of a drug detected).

Public Awareness to Drive Individual Action

NHTSA’s mission includes educating people about unsafe driving behaviors, including broadening understanding that drug-impaired driving is illegal and dangerous.

Over the next 6 months, NHTSA will:

NHTSA will work with its partners to develop robust and effective public education tools and campaigns, including an advertising campaign that focuses on the message that impaired driving includes both alcohol and drugs.

Pilot-test a training course for prosecutors and toxicologists to help them understand each other’s roles and how to work together when presenting evidence in court; and

Launch an online introductory training course to help highway safety professionals understand drug-impaired driving and how it differs from alcohol-impaired driving.

Over the next 12 months, NHTSA will:

Develop guidance to help States strengthen their foundation for drug-impaired driving programs, including potential legislative changes to test, track and inform enforcement and prevention efforts.

Policies for Improved Enforcement

NHTSA will work to explore and leverage innovative approaches to prevent driving under the influence of drugs through improved tools for law enforcement.

Over the next 6 months, NHTSA will:

Explore the potential to develop an allocation model to suggest an optimal number of drug recognition experts to support a geographic area and its population;

Continue to support the International Association of Chiefs of Police (IACP) at its annual training conference on drugs, alcohol and impaired driving in August; and

Continue its efforts to develop a field test for law enforcement, to assist officers in detecting and recognizing signs of cannabis impairment.

Going Forward: In addition to the steps outlined, NHTSA is committed to seeking further input through a series of regional meetings in the coming months, and to working closely with stakeholders in developing a vision for success and a plan for action.

Ideas, concerns, and thoughts

NHTSA wants you to join in the conversation about drug-impaired driving. Share your thoughts, concerns, ideas to us in an email. We'll summarize and add them to the appropriate idea board from the meeting.